In the field of radio communication systems, for the purpose to prevent increase of a code error ratio due to a burst error, generally Bose-Chaudhuri-Hocquenghem (BCH) error correction code (described as BCH code hereinafter), which is representative of multiple error correction cyclic code, is used.
As an example of a radio communication system, there is an advanced radio calling system (RCR STD-43) which selectively calls a pager as a mobile unit. This advanced radio calling system interleaves a BCH code and transmits the BCH code as a call signal to each pager.
Each pager has a decoder, deinterleaves the BCH codes according to the received call signal, and decodes the BCH code with the decoder into blocks each consisting of a plurality of words.
It should be noted that, as a technology similar to that described above, there has been disclosed, for instance, Japanese Patent Laid-Open Publication No. HEI 6-169261. This patent publication discloses a technology for selecting decoded data from among a plurality of types of candidate decoded data by referring to a metric indicating probability of a result of decoding as a reference when an error is detected.
However, in the decoder based on the conventional technology as described above, in a case where an error surpassing the BCH code error correction capability is generated in each word in a decoding process, a word error is generated, which makes it impossible to decode the BCH code.